Partial or complete loss of an individual's natural teeth, either or both at the upper and lower jaw, due to age, accident, diseases or other reasons has some serious effects on an individual both functionally and socially. Lack of teeth poses several serious functional problems such as not being able to chew, speech difficulties, etc. Even more so, a smile with a full set of white teeth is considered something to be desired, i.e. esthetics play an important role.
Utilization of a denture remains a problem. While dentures can be accurately fitted to the alveolar ridge of an individual, it is difficult to retain a denture in position. That is, during normal chewing or talking, the denture has a tendency to ride up out of position on the alveolar ridge, causing speech difficulties, chewing difficulties, and general unsatisfactory use of a denture.
Since the denture is an artificial appliance fitted against living tissue it is best to give that tissue a chance to rest without pressure for some period each day. Many people also have the habit of clenching their teeth when they sleep and this causes even more pressure against tissue and bone in the mouth. It is thus recommended that dentures be removed for some period of the day or night and treat the mouth and gums and clean the dentures.
The denture is a removable dental prosthesis which has artificial teeth embedded in a denture base resembling the gum or gingiva. The denture base provides the support for the prosthesis by resting on the gingiva. The underside of the denture base has a depression receptacle that receives at least a portion of the gingiva so as to provide a snug, reversible fit of the denture onto the gingiva that was adjacent to the lost teeth.
A full denture is used for replacing an entire set of teeth. A full denture would replace the lower set of teeth (“lower denture”) or upper set of teeth (“upper denture”). With the full denture, the surface of the depression receptacle base adheres to the appropriate gingiva of the denture wearer through saliva from the wearer's mouth causing a vacuum between the surface of the depression receptacle and the mucus membranes of the gingiva.
A bridge prosthesis is similar to that of a denture prosthesis except the bridge is normally limited to being a partial denture which is non-reversibly cemented or otherwise affixed to the adjacent teeth.
In recent years practice has developed of permanently implanting dental implants (at times referred to as dental fixtures or posts) in the bone structure of the mouth. These permanent dental implants are usually made of titanium which is more acceptable by the body's biological processes and which are locked into position by bone growth. By utilization of the permanently installed implants in the mouth of the individual, the possibility then exists for more readily securing a denture in place either fixedly or removably.
For example, U.S. Pat. No. 5,954,506 discloses a magnetic attachment used for retaining a dental prosthesis, comprising a male part which may be fixed to an abutment and a female part which may be fixed to the dental prosthesis. U.S. Pat. No. 5,997,300 discloses a stake anchored in the base or root of the tooth, and a covering cup is mounted on the denture. An engaging member is placed in the cup chamber, the engaging member being a soft plastic annular member. When a ball head on the stake is engaged therein, the denture is fixed in place, the denture can also be drawn out for removal, so that mounting and removal of the denture at the area missing teeth is convenient.
According to some other particular arrangements, the denture is mounted on an anchor member, which In turn is permanently secured to the individuals gum by means of permanently installed implants. The denture, according to several embodiments is detachable, and according to other embodiments is fixedly attached to said anchor member.
U.S. Pat. No. 4,184,252 is concerned with an overdenture structure and a method for securing it to the residual ridge of a patient. The nerve of at least one healthy tooth is removed and the root canal is filled with dental paste as in a root canal treatment. The crown of the tooth is removed near the gum line and a ferromagnetic bar is embedded in the filled root. Magnetic material is embedded in the overdenture in such position as to be aligned with the ferromagnetic bar at closure points. The dental material surrounding the ferromagnetic bar and the magnetic material embedded in the overdenture are shaped so as to provide contoured mating surfaces with one another. In an alternative embodiment, a root canal treatment is performed on two healthy teeth and bars are embedded in the roots of those teeth. A ferromagnetic rod is connected between the ends of the two bars. Magnetic material is embedded in the overdenture in position to be aligned with the entire length of the ferromagnetic rod. The dental material surrounding the ferromagnetic bars and the magnetic material embedded in the overdenture are shaped so as to provide contoured mating surfaces with one another
U.S. Pat. No. 4,784,608 is concerned with an attachment for removably supporting a denture in the mouth of the user in which the user has at least two spaced apart dental implants implanted therein, the attachment including a first basic portion in the form of an anchor member semi-permanently attached to the anchor implant and being curved to generally the shape of the alveolar ridge of the user and having a bar portion extending between the spaced apart dental implants, the anchor member having retention means at the ends thereof such as in the form of a recess at each end. The attachment second basic portion is a denture member which conforms generally to the contour of the anchor member and which is engageable in proximity with the anchor member. The denture member is cast within a denture having simulated gum portions and teeth portions. The denture member has retention means such as integrally formed implants which are removably insertable into the recess in the anchor member, the axis of the implants and the axis of the recesses being inclined toward planes of the anchor member and the denture member. The denture member includes an arm pivotal between a locked and an unlocked position. The arm has a blade portion which engages the anchor member at a point intermediate the retention means so that the arm when in the locked position retains the denture within the mouth of the user, the arm being engagable at its outer end by the fingernail of the user so that it can be pivoted to the unlocked position, allowing the denture to be removed.
U.S. Pat. No. 6,506,052 discloses a system of retrofitting non-dental implant secured dentures with dental implant technology in order to save time and expenses to the denture wearer and to provide a marketing capability that uses the benefits of retrofitted dentures as communicated to denture wearers to convince the denture wearers to receive dental implants. The retrofitting of the said denture comprises of modifying the depression receptacle of the denture base to accept a portion of the exposed part of at least one implant affixed to the denture wearer and to accept a portion of the dental implant securing device. A portion of the dental implant securing device is affixed to the depression receptacle so as to positioned dental implant securing device to reversible attach to at least a portion of the exposed art of at least one implant affixed to the denture wearer when the denture is affixed to the denture wearer.
Still another concept is at times referred to as the Novum™ system and is disclosed in the publication: ‘a new treatment concept for rehabilitation of the edentulous mandible. Preliminary results from a prospective clinical follow-up study’ [Clinical Implant Dentistry Related Res. 1999;1(1):2-16; by Branemark P I, Engstrand P, Ohrnell L O, Grondahl K, Nilsson P, Hagberg K, Darle C, Lekholm U.]
The present invention provides a system and a method for fixedly though removably supporting a denture in the mouth of an individual, wherein the denture is rigidly secured but in a way so that it is easily and conveniently removed and reinstalled in the individual's mouth, at a sturdy position.